By Neal Stephenson.
I can't really recommend this book. Before I read it (the first of his books that I've read, by the way), I was under the impression that he was a superb writer. Maybe he is now, but this book doesn't show it so much. The amount of profanity, sex, and what seems to me to be a dated view of the future (this book first came out in 1992) are fairly disenchanting. (Sometimes a dated view is charming, but ones that involve computers very much resembling our own tend to grate on me...)
Good things about this book: The characters, even the bad ones, are pretty likeable. Stephenson has a fair sense of humour or at least of the ludicrous and made me laugh quite a bit (for example, near the beginning the Mafia sends out a black helicopter to record a pizza delivery within the 30 minute time limit so they won't have to give away a free pizza). People carry around portable nuclear reactors.
Bad things: There is a large amount of profanity. This book reinterprets the Bible in a way I assume is similar to the DaVinci Code in its irreverence (though I haven't read the latter). Reading about a 15-year-old girl having sex is sad and appalling. The timeline is extremely unclear: when things happen seems to jump all over the place, especially near the beginning, and it's really weird that Y.T. and Hiro seem to be the best of buddies a day after meeting each other. In fact, the way it's written, it seems like this whole book only takes place over a week or two, but there must be a discontinuity somewhere because near the end it's mentioned that Y.T. and Hiro have gone out for fast food together many times and gotten to know each other, which is either not described earlier in the book, or I missed it.
I probably shouldn't have finished this book; I felt near the beginning that it probably wasn't worth reading. I certainly can't recommend it; perhaps Cryptonomicon will be better. (It's sitting on my shelf waiting...)